Like Tri-Valley, they had obtained permission from U.S. immigration officials to admit foreign students. "If there's a way to make a buck, some people will do it," said Brian Smeltzer, chief of the Counterterrorism and Criminal Exploitation Unit of U.S. Immigration and Customs Enforcement's Homeland Security Investigations. Government watchdogs say the recent visa fraud cases have exposed gaps in ICE's oversight of schools that admit foreign students — a problem the agency says is being corrected. At California Union University in Fullerton, owner Samuel Chai Cho Oh staged phony graduation ceremonies as part of a visa scheme, according to immigration officials. The school's founder and president, Susan Xiao-Ping Su, used more than $5.6 million she made in the scam to buy commercial real estate, a Mercedes Benz and multiple homes, federal prosecutors said. Prosecutors say he provided federal officials with false employment information about students, transcripts and a letter purporting to show another school accepted Herguan's credits. To be certified by immigration officials to accept foreign students, schools must be accredited by a Department of Education-approved organization or have their courses accepted by at least three accredited schools.